occurs when intercourse occurs during the fertile period of the cycle, that is, around the 12th -16th day. The period one week after the cycle and one week before the cycle is safe. I do not think there is a chance for you to get pregnant since you are in the safe period. Those cramps could possibly be the indication of the onset of your period. Anyway, take the advice of your doctor and go for a pregnancy test if needed. Take care.